SliverAppBar(
            backgroundColor: Colors.blue.withOpacity(0.7),
            leading: Icon(Icons.menu),
            actions: [
              
              Icon(Icons.notifications),
              Icon(Icons.search),
              
              ],
            pinned: true,
           
          
            expandedHeight: 200,
            floating: true,
            flexibleSpace: FlexibleSpaceBar(
              
              title: Text('Flutter Sliver'),
                centerTitle: true,
                background: Image(image: NetworkImage('https://pfps.gg/assets/banners/2547-illusion-gif.gif'), fit: BoxFit.cover,),

              ),
              
            ),